package com.warren.system.aspect;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.ImmutableList;
import com.warren.annotation.Limit;
import com.warren.enums.LimitType;
import com.warren.handler.BusinessException;
import com.warren.response.ResultCode;
import com.warren.util.IpUtils;
import com.warren.util.RequestHolder;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.stereotype.Component;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Method;

/**
 * @author warren
 * @create 2021-05-16 13:47
 * @Description
 */
@Slf4j
@Component
@Aspect
public class LimitAspect {
    private final RedisTemplate<Object,Object> redisTemplate;

    public LimitAspect(RedisTemplate<Object,Object> redisTemplate){
        this.redisTemplate = redisTemplate;
    }

    @Pointcut("@annotation(com.warren.annotation.Limit)")
    public void pointcut(){}

    @Around("pointcut()")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable{
        HttpServletRequest request = RequestHolder.getHttpServletRequest();
        MethodSignature signature = (MethodSignature)joinPoint.getSignature();
        Method signatureMethod = signature.getMethod();
        Limit limit = signatureMethod.getAnnotation(Limit.class);
        LimitType limitType = limit.limitType();
        String key = limit.key();
        if (StringUtils.isEmpty(key)){
            if (limitType == LimitType.IP){
                key = IpUtils.getIpAddr(request);
            }else {
                key = signatureMethod.getName();
            }
        }

        ImmutableList<Object> keys = ImmutableList.of(StringUtils.join(
                limit.prefix(),"_",key,"_",request.getRequestURI().replaceAll("/","_")
        ));
        System.out.println(keys);
        String luaScript = buildLuaScript();
        RedisScript<Long> redisScript = new DefaultRedisScript<>(luaScript, Long.class);
        Long count = redisTemplate.execute(redisScript, keys, limit.count(), limit.period());
        if (null != count && count.intValue() <= limit.count()) {
            log.info("第{}次访问key为 {}，描述为 [{}] 的接口", count, keys, limit.name());
            return joinPoint.proceed();
        } else {
            //throw new RuntimeException("访问次数受限制");
            //HttpServletResponse response = RequestHolder.getHttpServletResponse();
            //writeJosn(response,"访问次数受限制");
            throw new BusinessException(ResultCode.LIMIT_ERROR.getCode(),ResultCode.LIMIT_ERROR.getMessage());


        }
    }

    /**
     * 限流脚本
     */
    private String buildLuaScript() {
        return "local c" +
                "\nc = redis.call('get',KEYS[1])" +
                "\nif c and tonumber(c) > tonumber(ARGV[1]) then" +
                "\nreturn c;" +
                "\nend" +
                "\nc = redis.call('incr',KEYS[1])" +
                "\nif tonumber(c) == 1 then" +
                "\nredis.call('expire',KEYS[1],ARGV[2])" +
                "\nend" +
                "\nreturn c;";
    }

    
}
